EP3478797B1 - Method for treating a hydrocarbon feedstock comprising a deasphalting step and an asphalt conditioning step - Google Patents

Description

The present invention relates to the treatment of heavy fractions of hydrocarbons containing inter alia sulfur impurities, metals and asphaltenes. It relates more particularly to a process for treating heavy petroleum charges of the atmospheric residue and / or vacuum residue type for the production of a majority fraction with reduced content of impurities and of a minority fraction concentrating the impurities.

The process according to the invention can be qualified as a carbon rejection process of the deasphalting type. The majority fraction with a reduced content of impurities can thus be more easily recovered as such or via another refining process.

In the field of the treatment of heavy hydrocarbon fractions, in particular in deasphalting, one of the problems encountered lies in the operability of the asphalt fraction which is found to be at the origin of phenomena of fouling and clogging of the units. This results in frequent shutdowns of the units for cleaning and harms the efficiency and profitability of such processes.

Asphalt can be characterized by its softening point. A softening point of 160 ° C means a viscosity at this temperature of 1 million to 2 million centistokes (cSt) at this temperature. We can deduce a viscosity of the order of 500 cSt at the outlet temperature of an asphalt stripping unit (or stripper according to English terminology) operated at 280 ° C. Under such conditions the evacuation of the asphalt and its flow to a step of upgrading the asphalt such as fluxing, gasification, solidification etc. is imperfect (classic scheme where the asphalt flows by gravity and by pressure difference between the two stages stripping and solidification).

It is also known that the maximum viscosity for pumping the asphalt fraction is of the order of 2000 cSt, but for reasons of operational reliability it is recommended to be around 200 cSt; Since the processes can fluctuate in temperature, it is often preferable to operate between 10 to 50 ° C above the temperature at which the pumpability limit is reached (2000 cSt).
These problems often limit the efficient use of asphalt. The current state of the art does not make it possible to extract asphalts having a softening point greater than 160 ° C. in liquid form, under conditions of satisfactory reliability with respect to the risk of clogging. FR 3 014 110 discloses a process for treating a hydrocarbon feedstock incorporating deasphalting.

An objective of the invention is to improve the efficiency of the treatment process by eliminating the unitary step of stripping the asphalt which generally consists of equipment capable of fouling. The invention proposes in particular to integrate the stripping of the asphalt and its solidification in a dynamic conditioning system which mixes stirs or grinds the asphalt during its cooling, by means of a screw or rotary system (internal rotating) in order to be freed from the intermediate viscosity constraint and to avoid plugging phenomena.
The Applicant has therefore developed a new deasphalting process incorporating a step of conditioning the asphalt in solid form so as to make it easily transportable. The integration of the asphalt conditioning step being particularly advantageous when the deasphalting conditions lead to obtaining an asphalt with a high softening point, for example during a deasphalting using a solvent or a mixture of solvents of similar polarity, or using a mixture of solvents of different polarity.

More specifically, the invention relates to a method as defined in claim 1.

According to the invention, the asphalt or asphalt fraction produced by the process has a softening point without solvent and without flux (measured according to the Ball and Ring method of standard EN 1427 or Ring and Ball of standard ASTM D36, or EN 1427 ) greater than 120 ° C, preferably greater than 160 ° C, more preferably between 120 and 250 ° C, more preferably between 160 and 250 ° C, more preferably between 120 and 220 ° C, more preferably between 160 and 220 ° C.

• La possibilité de produire un asphalte sous forme solide à très haut point de ramollissement dont le soutirage peut être facilité par un fluxant de soutirage ;
• L'obtention à haut rendement d'huile désalphatée à teneur réduite en impuretés, valorisable telle quelle ou dans un autre procédé de raffinage ;
• La récupération d'au moins une partie du fluxant de soutirage, du solvant ou du mélange de solvants, ce qui évite sa perte avec l'asphalte ;
• La possibilité d'éliminer l'étape unitaire conventionnelle de strippage (étape d) qui est généralement constitué d'un équipement susceptible de s'encrasser.

According to the invention, sub-steps f) and g) are carried out in at least two sub-units or in a single unit equipped with at least one means capable of keeping in motion or of stirring or grinding of continuously the asphalt fraction, at least one heating and cooling means and at least means capable of removing the solvent, the mixture of solvents and / or the fluxing agent from the process.
Among the advantages of the present invention, it may be noted:

• The possibility of producing an asphalt in solid form with very high softening point, the drawing off of which can be facilitated by a drawing flux;
• Obtaining high-yield desalphated oil with a reduced content of impurities, recoverable as it is or in another refining process;
• The recovery of at least part of the withdrawal flux, of the solvent or of the mixture of solvents, which prevents its loss with the asphalt;
• The possibility of eliminating the conventional unitary stripping step (step d) which generally consists of equipment liable to clog.

Description of the figures

• La figure 1 illustre une vue schématique du procédé selon une première mise en œuvre de l'invention:
  • La charge (1) est introduite en mélange avec un solvant ou un mélange de solvants (2) dans une étape a) d'extraction permettant d'obtenir au moins une fraction (3) comprenant de l'huile désasphaltée et du solvant ou du mélange de solvants et une fraction (6) comprenant de l'asphalte et du solvant ou du mélange de solvants. Une partie du solvant ou du mélange de solvants est généralement introduite en mélange avec la charge en un premier point de l'extracteur tandis qu'une autre partie peut être injectée seule en un point différent selon un flux non représenté, ce point étant de préférence plus bas que le premier point, donc proche du fond du même extracteur.
  • Une étape b) de séparation de la fraction (3) comprenant de l'huile désasphaltée et du solvant ou du mélange de solvants issue de l'étape a) d'extraction, permet d'obtenir au moins une huile désasphaltée (5) et une partie du solvant ou du mélange de solvants (4) introduit à l'étape a) d'extraction.
  • Une étape c) d'injection de fluxant de soutirage (7) dans la fraction (6) comprenant de l'asphalte et du solvant ou du mélange de solvants issue de l'étape a) d'extraction, permettant d'obtenir une fraction (8) moins visqueuse que la fraction (6).
  • Une étape d) de séparation de la fraction (8) moins visqueuse comprenant de l'asphalte, du solvant ou du mélange de solvants, et du fluxant de soutirage, issue de l'étape c), permettant de préférence de séparer au moins une fraction asphalte (10) d'au moins une partie du solvant ou du mélange de solvants (9) introduit à l'étape a) d'extraction.
  • Une étape e) d'injection de fluxant de soutirage (11) dans la fraction (10) issue de l'étape d) de séparation, permettant d'obtenir une fraction (12) moins visqueuse que la fraction (10).
  • Une étape de conditionnement de la fraction asphalte issue des étapes a) et/ou c) et/ou d) et/ou e), sous forme solide mise en œuvre en sous-étapes successives ou simultanées :
    • o une sous-étape f) de séparation de la fraction (12) issue de l'étape e) permettant de récupérer au moins en partie le fluxant de soutirage introduit dans les étape c) et e) d'injection, éventuellement le solvant ou le mélange de solvants, et une fraction asphalte (14),
    • o une sous-étape g) de solidification de l'asphalte (14) issu de la sous-étape f) de séparation permettant de récupérer une fraction asphalte conditionnée sous forme solide (15).
• La figure 2 illustre une variante de la mise en œuvre selon la figure 1. Dans cette variante, l'étape c) optionnelle d'injection de fluxant de soutirage n'est pas mise en œuvre et la fraction (6) comprenant de l'asphalte et du solvant ou du mélange de solvants est introduite directement dans l'étape d) de séparation. Le reste de la mise en œuvre est similaire à la description de la figure 1.
• La figure 3 illustre une variante de la mise en œuvre selon la figure 1. Dans cette variante, l'étape e) optionnelle d'injection de fluxant de soutirage n'est pas mise en œuvre et la fraction (10) comprenant de l'asphalte et au moins une partie du fluxant de soutirage introduit à l'étape c), est introduite directement dans l'étape intégrée de conditionnement de la fraction asphalte. Le reste de la mise en œuvre est similaire à la description de la figure 1.
• La figure 4 illustre une variante de la mise en œuvre selon la figure 1. Dans cette variante, l'étape d) optionnelle de séparation du solvant ou du mélange de solvants n'est pas mise en œuvre et la fraction (8) comprenant de l'asphalte et du fluxant de soutirage introduit à l'étape c), est introduite directement dans l'étape intégrée de conditionnement de la fraction asphalte au cours de laquelle le solvant ou le mélange de solvants et le fluxant de soutirage seront éliminés. Le reste de la mise en œuvre est similaire à la description de la figure 1.
• La figure 5 illustre une variante de la mise en œuvre selon la figure 1. Dans cette variantes les étapes c) et e) d'injection de fluxant, ainsi que l'étape d) de séparation ne sont pas mises en œuvre. La fraction (6) comprenant de l'asphalte et du solvant ou du mélange de solvants issue de l'étape a) est introduite directement dans l'étape intégrée de conditionnement de la fraction l'asphalte au cours de laquelle le solvant ou le mélange de solvants seront éliminés. Le reste de la mise en œuvre est similaire à la description de la figure 1.
• La figure 6 représente de manière schématique toutes les variantes possibles de l'invention avec des flux en pointillés représentant le court-circuitage éventuel de chaque étape optionnelle.

The descriptions below constitute examples of implementation of the invention without limiting its scope. For the sake of simplicity, only the main stages are shown, but it is understood that all the equipment necessary for operation is present (tanks, pumps, exchangers, ovens, columns, etc.). Only the main flows are represented.

• The figure 1 illustrates a schematic view of the method according to a first implementation of the invention:
  • The feed (1) is introduced as a mixture with a solvent or a mixture of solvents (2) in an extraction step a) making it possible to obtain at least one fraction (3) comprising deasphalted oil and solvent or mixture of solvents and a fraction (6) comprising asphalt and solvent or mixture of solvents. A part of the solvent or of the mixture of solvents is generally introduced in mixture with the feed at a first point of the extractor while another part can be injected alone at a different point according to a flow not shown, this point being preferably lower than the first point, so close to the bottom of the same extractor.
  • A step b) of separation of the fraction (3) comprising deasphalted oil and of the solvent or mixture of solvents resulting from step a) of extraction, makes it possible to obtain at least one deasphalted oil (5) and part of the solvent or mixture of solvents (4) introduced in step a) of extraction.
  • A step c) of injecting withdrawal flux (7) into the fraction (6) comprising asphalt and solvent or mixture of solvents from step a) of extraction, making it possible to obtain a fraction (8) less viscous than fraction (6).
  • A step d) of separation of the less viscous fraction (8) comprising asphalt, solvent or mixture of solvents, and the withdrawal flux, resulting from step c), preferably making it possible to separate at least one asphalt fraction (10) of at least part of the solvent or mixture of solvents (9) introduced in step a) of extraction.
  • A step e) of injecting withdrawal flux (11) into the fraction (10) resulting from the separation step d), making it possible to obtain a fraction (12) less viscous than the fraction (10).
  • A step of conditioning the asphalt fraction resulting from steps a) and / or c) and / or d) and / or e), in solid form, implemented in successive or simultaneous substeps:
    • a sub-step f) of separation of the fraction (12) resulting from step e) making it possible to recover at least in part the withdrawal flux introduced in steps c) and e) of injection, optionally the solvent or the mixture of solvents, and an asphalt fraction (14),
    • o a sub-step g) of solidification of the asphalt (14) resulting from the sub-step f) of separation making it possible to recover an asphalt fraction conditioned in solid form (15).
• The figure 2 illustrates a variant of the implementation according to the figure 1 . In this variant, the optional step c) of injection of withdrawal flux is not implemented and the fraction (6) comprising asphalt and solvent or mixture of solvents is introduced directly into the step d) separation. The rest of the implementation is similar to the description of the figure 1 .
• The figure 3 illustrates a variant of the implementation according to the figure 1 . In this variant, the optional step e) of injection of withdrawal flux is not implemented and the fraction (10) comprising asphalt and at least part of the withdrawal flux introduced in step c ), is introduced directly into the integrated step of conditioning the asphalt fraction. The rest of the implementation is similar to the description of the figure 1 .
• The figure 4 illustrates a variant of the implementation according to the figure 1 . In this variant, the optional step d) of separation of the solvent or of the mixture of solvents is not implemented and the fraction (8) comprising asphalt and drawing-off flux introduced in step c), is introduced directly into the integrated step of conditioning the asphalt fraction during which the solvent or the mixture of solvents and the drawing-off flux will be eliminated. The rest of the implementation is similar to the description of the figure 1 .
• The figure 5 illustrates a variant of the implementation according to the figure 1 . In this variant, steps c) and e) of injecting fluxing agent, as well as step d) of separation, are not implemented. The fraction (6) comprising asphalt and solvent or mixture of solvents from step a) is introduced directly into the integrated step of conditioning the asphalt fraction during which the solvent or the mixture solvents will be removed. The rest of the implementation is similar to the description of the figure 1 .
• The figure 6 represents schematically all the possible variants of the invention with dotted flows representing the possible short-circuiting of each optional step.

It is understood that in the preceding figures, the solvent (s), the drawing flux (s) which may be identical or different, originating from the separation steps can at least partly be recycled in the process and additions can also be made.

detailed description Load

The feedstock treated in the process according to the invention is advantageously a hydrocarbon feedstock having a C7 asphaltene content of at least 1% by mass, preferably at least 2% by mass relative to the feedstock, an initial boiling point of at least 340 ° C, preferably at least 450 ° C, and a final boiling temperature of at least 550 ° C, preferably at least 600 ° C.

The hydrocarbon feedstock according to the invention can be chosen from atmospheric residues, vacuum residues from direct distillation, crude oils, headless crude oils, oil sands or their derivatives, oil shales or their derivatives, oils from parent rock or their derivatives, taken alone or in a mixture. In the present invention, the fillers which are treated are preferably atmospheric residues or vacuum residues, or mixtures of these residues, and more preferably vacuum residues.

The hydrocarbon feedstock treated in the process may contain, among other things, sulfur impurities. The sulfur content may be at least 0.1% by mass, at least 0.5% by mass, preferably at least 1% by mass, more preferably at least 2% by mass relative to chargeable.

The hydrocarbon feed treated in the process may contain, among other things, asphaltenes. The content of C7 asphaltenes may be at least 1% by mass, preferably at least 2% by mass relative to the filler.

The hydrocarbon feedstock treated in the process may contain, among other metals. The nickel + vanadium content may be at least 10 ppm, preferably at least 30 ppm.

The hydrocarbon feedstock treated in the process may contain, among other things, Conradson carbon. The Conradson carbon content can be at least 2% by mass, preferably at least 5% by mass relative to the filler.

Step a) of extraction

The load according to the invention is subjected to an extraction step a) preferably carried out under specific conditions making it possible to obtain a deasphalted oil preferably with a high yield and an asphalt fraction preferably obtained in lower quantity.

Extraction step a) can be carried out in one or more steps, by bringing the charge into contact with a solvent containing hydrocarbons, so as to obtain an asphalt fraction and a deasphalted oil fraction called DAO, step a ) being advantageously implemented under the subcritical conditions for the solvent or the mixture of solvents used. A nonpolar solvent or a mixture of polar and nonpolar solvents can be used. Preferably, a mixture of at least one polar solvent and at least one apolar solvent is used.
When step a) of extraction is carried out using a combination of polar and non-polar solvents, this makes it possible to go further in maintaining the solubilization in the oil matrix of all or part of the structures. polar heavy resins and asphaltenes which are the main constituents of the asphalt phase. We then speak of selective unsalting as implemented in the patent FR 2 999 597B . Selective deasphalting thus makes it possible to choose which type of polar structures remain dissolved in the deasphalted oil matrix. Consequently, it makes it possible to selectively extract only a portion of this asphalt from the load, that is to say the most polar structures and those most refractory to hydrotreating and hydrocracking.
Step a) can be carried out in an extraction column or extractor, or in a mixer-settler. Step a) is preferably carried out in an extraction column containing liquid-liquid contactors (packing elements and / or trays, etc.) placed in one or more zones. Preferably, the solvent or the mixture of solvents according to the invention is introduced into the extraction column at two different levels. Preferably, the feed according to the invention is introduced into an extraction column at a single introduction level, generally in admixture with at least part of the solvent and generally below a first zone of liquid-liquid contactors. Preferably, the other part of the solvent or mixture of solvents is injected lower than the load, generally below a second zone of liquid-liquid contactors, the load being injected above this second zone of contactors.
Step a) is carried out under subcritical conditions for said solvent or mixture of solvents. Step a) is carried out at an extraction temperature advantageously between 50 and 350 ° C, preferably between 80 and 320 ° C, more preferably between 120 and 310 ° C, even more preferably between 150 and 300 ° C, and a pressure advantageously between 0.1 and 6 MPa, preferably between 1 and 6 MPa, more preferably between 2 and 5 MPa.

The ratio or volume ratio of the solvent or of the mixture of solvents according to the invention (volume of polar solvent + volume of non-polar solvent) on the mass of liquid hydrocarbon fraction resulting from step a) is generally between 1/1 and 10/1, preferably between 2/1 to 8/1 expressed in liters per kilogram. This report includes all of the solvent or mixture of solvents which can be divided into several injection points.

The polar solvent used can be chosen from pure aromatic or naphtheno-aromatic solvents, polar solvents comprising heteroelements, or a mixture thereof. The aromatic solvent is advantageously chosen from monoaromatic hydrocarbons, preferably benzene, toluene or xylenes alone or as a mixture; diaromatics or polyaromatics; naphtheno-aromatic hydrocarbons such as tetralin or indane; heteroatomic aromatic hydrocarbons (oxygenated, nitrogenous, sulfur) or any other family of compounds having a more polar character than saturated hydrocarbons such as for example dimethylsulfoxide (DMSO), di-methylformamide (DMF), tetrahydrofuran (THF). The polar solvent used in the process according to the invention can be a cut rich in aromatics. The aromatic-rich cuts according to the invention can be, for example, cuts originating from the FCC (Fluid Catalytic Cracking according to Anglo-Saxon terminology) such as heavy petrol or LCO (Light Cycle Oil according to Anglo-Saxon terminology) or from petrochemical or refinery units. Mention should also be made of cuts derived from coal, from biomass or from a biomass / coal mixture with possibly a residual petroleum charge after thermochemical conversion with or without hydrogen, with or without catalyst. Preferably, the polar solvent used is a pure monoaromatic hydrocarbon or in admixture with an aromatic hydrocarbon.

According to an extraction variant using a combination of polar and non-polar solvents, a mixture of polar and non-polar solvents is injected at a point while a solvent or a mixture of polar and non-polar solvent (s) is injected at a second point. According to this variant, preferably, a polar solvent heavier than the non-polar solvent is injected at the lowest point.

The apolar solvent used is preferably a solvent composed of saturated hydrocarbon (s) comprising a carbon number greater than or equal to 3, preferably between 3 and 9. These solvents are used pure or as a mixture (for example : mixture of alkanes and / or cycloalkanes or else light petroleum cuts such as naphtha). Preferably, the non-polar solvent contains hydrocarbons having a carbon number greater than or equal to 4 and less than or equal to 7, very preferably, the non-polar solvent contains hydrocarbons having a carbon number greater than or equal to 5 and less or equal to 7, this so as to obtain an asphalt with a high softening point suitable for the invention and to obtain deasphalted oil with a high yield.

Advantageously, the ratio or volume ratio (v / v) of the apolar solvent to the polar solvent is greater than 50/50, preferably greater than 60/40 and very preferably greater than 70/30.

Advantageously, the boiling point of the polar solvent of the mixture of solvents according to the invention is higher than the boiling point of the non-polar solvent.

The choice of the temperature and pressure conditions of the extraction combined with the choice of the nature of the solvents and the choice of the possible combination of apolar and polar solvents in step a) of extraction (or deasphalting) make it possible to adjust extraction performance. Step a) allows, thanks to specific deasphalting conditions, to go further in maintaining the solubilization in the oil matrix of all or part of the polar structures of heavy resins and asphaltenes which are the main constituents of the asphalt phase in the case of conventional deasphalting. This results in an improved yield of deasphalted oil.

At the head of the extraction column or of the mixer-settler, preferably above the highest liquid-liquid contactor zone (s), we recover a fraction which comprises deasphalted oil (deasphalted oil called DAO) and part of the solvent or mixture of solvents according to the invention.

At the bottom of the extraction column or of the mixer-settler, preferably below the lowest contactor zone (s), a fraction is recovered which comprises asphalt and part of the solvent or mixture of solvents according to the invention.

The solvent or mixture of solvents consists of a make-up and / or of a part recycled during steps b), d) and / or of sub-step f). These additions are necessary to compensate for the losses of solvent in the asphalt fraction and / or the deasphalted oil fraction. These losses are low but cannot be avoided because of the imperfect separation steps by definition.

Step b) of separation of the fraction comprising deasphalted oil

The fraction comprising deasphalted oil from step a) of extraction is subjected to a separation step b) making it possible to obtain at least one deasphalted oil and part of the solvent or mixture of solvents introduced into the step a) of extraction. The solvent or mixture of solvents recovered can be recycled upstream of the extraction column.

This separation step for purifying and separating the deasphalted oil and the solvent can implement all the necessary equipment known to those skilled in the art (separator flasks, distillation or stripping columns, heat exchangers, ovens, pumps , compressors, etc.). An inert gas can be used for stripping.

The deasphalted oil contains lower impurity contents than that of the filler. The yield of deasphalted oil is high, at least 50% by mass of the starting charge, preferably greater than 70% by mass of the starting charge.

The deasphalted oil can advantageously be used in another refining process.

Step c) optional fluxant injection

Optionally, a withdrawal flux can be injected in a mixture with the fraction comprising asphalt from step a). Preferably, the fluxing agent is injected at at least one point in the bottom of the extraction column used in step a), this or these injection points being located below the lowest point of solvent injection or mixture of solvents introduced into the extraction column used in step a), preferably below the lowest liquid-liquid contactor zone (s) but above the bottom flange of the extraction column used in step a), that is to say at the outlet of the fraction comprising the asphalt.

The use of racking flux facilitates the evacuation of the asphalt-rich fraction by reducing the viscosity and limits the fouling of the lines and equipment located downstream. Step c) and / or e) of injecting fluxing withdrawal is advantageous when the softening point of the asphalt is greater than 160 ° C.

The fluxing agent is generally a cut containing hydrocarbons, preferably aromatic. This fluxing agent can advantageously be chosen from monoaromatics (benzene, toluene, xylenes), gasoline cuts of preference originating from catalytic reforming or from a thermal process such as catalytic cracking, diesel cuts preferably originating from conversion process into absence of hydrogen, for example an LCO type cut from a catalytic cracking process, or aromatic extracts such as those from production lines of lubricating oils. Preferably, the fluxing agent is a heavy gasoline resulting from a catalytic cracking whose end point is at most 250 ° C., more preferably, the boiling range of the fluxing agent is between 150 and 220 ° C.

The draw-off flux may consist of a make-up and a part recycled during step d) or sub-step f). This back-up is necessary to compensate for any losses which are small but cannot be avoided because of the imperfect separation steps by definition.

At the end of step c), a fraction is obtained comprising asphalt, solvent or mixture of solvents introduced during step a).

Step d) optional separation of the fraction comprising asphalt

The fraction comprising asphalt from step a) of extraction or from step c) of fluxing injection, can be subjected to an optional step d) of separation making it possible to separate an asphalt fraction alone or mixed with a solvent withdrawal flux or the solvent mixture introduced in step a) of extraction. The solvent or mixture of solvents recovered can be recycled upstream of the extraction column in step a).

This separation step for purifying and separating the asphalt fraction from the solvent or the mixture of solvents can use all the necessary equipment (separator flasks, distillation or stripping columns, heat exchangers, ovens, pumps, compressors, etc. .). Advantageously, an inert gas is injected at the bottom of the stripping column.

At the end of step d), an asphalt fraction is optionally comprising fluxing agent if the optional step c) of injecting the fluxing agent has been implemented. In a variant, step d) can make it possible to separate at least a portion of fluxing agent, when a fluxing agent is injected in step c).

Step e) optional fluxant injection

Optionally, a drawing-off flux can be injected as a mixture with the asphalt fraction resulting from step d) optionally comprising flux if the optional step c) of injecting the flux has been implemented. Preferably, the fluxing agent is injected at at least one point in the bottom of the stripping column used in step d) when it is implemented.

The use of racking flux facilitates the evacuation of the asphalt-rich fraction by reducing the viscosity and limits the fouling of the lines and equipment located downstream. Step c) and / or e) of injecting fluxing withdrawal is advantageous when the softening point of the asphalt is greater than 160 ° C. This flux is generally a cut containing hydrocarbons, preferably aromatic, preferably of the same kind as the flux defined during step c) of injection of the flux. The optional racking flux can be made up and a part recycled during step d) or sub-step f). This back-up is necessary to compensate for any losses which are small but cannot be avoided because of the imperfect separation steps by definition.
At the end of step e), an asphalt fraction comprising fluxing agent is obtained.

Integrated step for conditioning the asphalt fraction comprising sub-steps f) and g) Sub-step f)

• une sous-étape f) pendant laquelle la fraction asphalte est chauffée à une température comprise entre 120 et 340°C et supérieure au point de ramollissement de l'asphalte,
• une sous-étape g) pendant laquelle l'asphalte séparé du solvant, du mélange de solvants et/ou du fluxant est refroidi à une température inférieure au point de ramollissement de l'asphalte.

La sous-étape f) permet de récupérer le solvant ou le mélange de solvants issu de l'étape a) d'extraction en l'absence de l'étape d) (ou lorsque la séparation du solvant ou mélange de solvants en d) est incomplète) et éventuellement le fluxant de soutirage lorsque celui-ci est mis en œuvre lors de l'étape c) et/ou de l'étape e) d'injection de fluxant de soutirage. Cette sous-étape f) permet également de récupérer une fraction asphalte séparé du solvant, du mélange de solvants et/ou du fluxant.The process of the present invention comprises an integrated step of conditioning the asphalt fraction resulting from steps a) and / or c) and / or d) and / or e), in solid form, implemented in successive or simultaneous substeps. :

• a sub-step f) during which the asphalt fraction is heated to a temperature between 120 and 340 ° C and higher than the softening point of the asphalt,
• a sub-step g) during which the asphalt separated from the solvent, from the mixture of solvents and / or from the fluxing agent is cooled to a temperature below the softening point of the asphalt.

Sub-step f) makes it possible to recover the solvent or the mixture of solvents resulting from step a) of extraction in the absence of step d) (or when the separation of the solvent or mixture of solvents in d) is incomplete) and possibly the withdrawal flux when it is used during step c) and / or step e) of injection of withdrawal flux. This sub-step f) also makes it possible to recover an asphalt fraction separated from the solvent, from the mixture of solvents and / or from the fluxing agent.

This sub-step f) of separation is implemented for asphalt fractions having a softening point without solvent and without fluxing agent. greater than 120 ° C, preferably greater than 160 ° C, more preferably between 120 and 250 ° C, more preferably between 160 and 250 ° C, more preferably between 120 and 220 ° C, more preferably between 160 and 220 ° C. Sub-step f) of separation is carried out at a temperature between 120 and less than or equal to the cracking temperature of hydrocarbons estimated at 340 ° C (temperature generally accepted in vacuum distillations and not leading to excessive cracking) . The separation sub-step f) is preferably carried out at a temperature above the boiling point of the solvent, of the mixture of solvents and / or optionally of the fluxing agent.
The separation sub-step f) is preferably carried out at a low pressure, between 0.1 and 2 MPa, preferably between 0.1 and 1 MPa. Sub-step f) can be operated by stripping. Sub-step f) can also be carried out under vacuum or else under the regime of a unitary pressure operation followed by a unitary vacuum operation. When the removal of at least part of the solvent, of the mixture of solvents and / or optionally of the fluxing agent is carried out by stripping during sub-step f), the pressure is preferably lower than the vapor pressure of the solvent, of the mixture of solvents and / or of the fluxing agent which it is desired to eliminate.
This separation sub-step making it possible to purify and separate the asphalt and the solvent or the mixture of solvents and / or the fluxing agent can use all the necessary equipment (separating flasks, distillation or stripping columns, heat exchangers, ovens, pumps, compressors, etc.). The solvent or mixture of solvents and / or the flux) can therefore be vaporized, distilled or stripped. Advantageously, an inert gas can be injected to facilitate stripping.
During the removal of the solvent or mixture of solvents and / or fluxing agent, the asphalt fraction becomes more and more viscous. It then becomes particularly relevant that sub-step f) is carried out in a sub-unit or a unit comprising the use of equipment making it possible to keep in motion or stir or knead or knead mechanically the fraction comprising the asphalt throughout sub-step f) and as the solvent, solvent mixture and / or flux is removed, in order to avoid clogging of equipment.

To reach the desired temperature, the fraction comprising asphalt from step e) can be heated at the inlet or during sub-step f), the ideal being preferably that the equipment or equipment making it possible to maintain in motion the asphalt fraction during the removal of the solvent, the mixture of solvents and / or the fluxing agent, is equipped with a heating system. This or these equipment must also allow the evacuation of the solvent, the mixture of solvents and / or flux stripped and / or vaporized, for example by means of one or more vents, preferably located in upper part of the equipment (s) used. The solvent, the mixture of solvents and / or the flux thus recovered can be condensed and at least partly recycled towards steps a) of extraction, or steps c) and / or e) of injection of flux.

Among the equipment that can be used, sub-step f) can include, for example, equipment used in the manufacture of polymers, such as devolatilization equipment, kneaders, reactor-extruders, extruders, extruder-kneaders, kneaders, reactors-kneaders, mixers, mixer-reactors, mixer-kneaders. Preferably, sub-step f) can comprise as main equipment a kneading reactor (kneader reactor according to English terminology), preferably equipped with a heating system.

Sub-step f) comprises a mechanical device, for example a pump optionally supplemented by a valve system, making it possible to evacuate the asphalt towards sub-step g) of the integrated conditioning step.

Sub-step g)

The asphalt fraction resulting from sub-step f) is subjected to a sub-step g) aimed at obtaining the asphalt in solid form, to make it more easily transportable and recoverable.
It is understood that when the sub-steps f) and g) can be implemented successively, the asphalt separated from the solvent, from the mixture of solvents and / or from the flux introduced into the sub-step g) comes from sub-step f).
It is understood that sub-steps f) and g) can be implemented simultaneously in the case where the operating conditions lead to the entrainment of the solvent, optionally using an inert stripping gas, and when said conditions are sufficient to cause simultaneous cooling of the asphalt.

This sub-step g) is implemented for asphalt fractions having a softening point excluding solvent and non-fluxing agent (measured according to the Ball and Ring method of standard EN 1427 or Ring and Ball of standard ASTM D36) greater than 120 ° C, preferably greater than 160 ° C, more preferably between 120 and 250 ° C, more preferably between 160 and 250 ° C, more preferably between 120 and 220 ° C, more preferably between 160 and 220 ° C.
Sub-step g) is carried out at a temperature below the softening point of the asphalt, preferably at least 25 ° C lower than the softening point, preferably at least 50 ° C lower than the softening point , more preferably at least 100 ° C lower than the softening point. For most asphalts, for example having a softening point between 120 and 250 ° C, the greater the difference between the cooling temperature and the softening point, the easier the solidification of the asphalt. In cases where the softening point of the asphalt is very high, for example greater than 200 ° C, the temperature of sub-step g) will advantageously be less than 200 ° C, preferably less than 175 ° C, preferably less than 150 ° C, more preferably less than 100 ° C.

Sub-step g) is preferably carried out at a low pressure, between 0.1 and 2 MPa, preferably between 0.1 and 1 MPa. Sub-step g) can also be operated in vacuum, preferably in slight vacuum, so as to evacuate any asphalt dust towards a dedusting system. Sub-step g) can also include a unit operation under pressure followed by a unit operation under vacuum.

During sub-step g), the asphalt fraction cools, becomes more viscous, then it can change state and be in solid form. It then becomes particularly relevant that sub-step g) can be carried out in a sub-unit or a unit comprising the use of equipment making it possible to keep moving or to stir or to knead or to knead mechanically or to grind the asphalt fraction all along sub-step g) and as it cools, this in order to obtain asphalt in the form of divided solids and to avoid clogging of the equipment.

This packaging sub-step can implement all the necessary equipment (tanks, heat exchangers, ovens, pumps, valves, etc.). Among the equipment that can be used, sub-step g) may include, for example, kneaders, grinders, reactor-extruders, extruders, extruder-kneaders, kneaders, reactor-kneaders, mixers, reactor mixers, mixer-kneaders.

Preferably, sub-step g) comprises as a main equipment a kneader reactor ('kneader reactor' according to English terminology), preferably equipped with a cooling system.

Sub-step g) may include a mechanical device, for example a vibrating tube possibly supplemented by means for evacuating the asphalt in solid form to a repository.

The equipment of sub-steps f) and g) may be the same so as to ensure continuity between the two sub-units.

The solid asphalt resulting from sub-step g) may be in the form of pieces of asphalt (ground, extruded or powder) the largest dimension of which does not exceed 10 cm, preferably 5 cm, more preferably 1 cm. The state of divided solids of the asphalt obtained in sub-step g) is an important criterion which allows this asphalt fraction to be easily transportable and recoverable unlike liquid asphalts which need to be constantly heated to be transported or fluxed asphalts which require a large amount of fluxing agents.

The solid asphalt produced by the process according to the invention can, for example, be used as a fuel for the production of cements, electricity or steam, or even be gasified to produce a synthesis gas or hydrogen.

EXAMPLES

The following examples are made with a charge A vacuum residue of Arabian Heavy origin. The percentages are expressed in mass (m) unless otherwise indicated. <u><b> Table 1 </b>: <b> Characteristics of load A </b></u> Density 15/4 1.026 Sulfur (% m / m) 5.4 Conradson carbon (% m / m) 22 Asphaltenes C7 (% m / m) (standard NF T60-115) 12 Ni + V (ppm) 202 Fraction 540 ° C + (% m / m) 82

Example 1

In the first example, conventional deasphalting is carried out, ie extraction of the feed A with n-pentane as solvent under the operating conditions presented in Table 2 (step a). <b><u> Table 2: Operating conditions for conventional deasphalting on load A </u></b> Solvent nC5 Solvent / charge ratio (v / m) 6/1 Pressure (MPa) 4.76 Temperature (° C) 180

At the end of the extraction step, a fraction containing deasphalted oil and n-pentane is obtained. This fraction is subjected to a separation step so as to separate the pentane and the deasphalted oil (DAO), the characteristics of which are presented in Table 3. <b><u> Table 3: Yields and characteristics of the deasphalted DAO oil obtained </u></b> CAD yield (% m / m of the load) 65 Density 15/4 0.985 Sulfur (% m / m) 4.3 Conradson carbon (%) 10 Ni + V (ppm) 36 AC7 <0.05

At the end of the extraction step, a fraction containing asphalt and n-pentane is also obtained.

In a first variant, this fraction is subjected to a separation step so as to separate the n-pentane and the asphalt (step d). An asphalt is obtained with 35% mass of yield compared to the load. In a second variant, the separation step d) is not implemented.

In both cases, the asphalt or the non-separated asphalt fraction is subjected to a conditioning step according to the invention.

According to the second variant, the asphalt fraction is subjected to a conditioning step allowing a temperature of 50 ° C. and a pressure of 0.3 MPa making it possible to separate the n-pentane (sub-step f)) and to solidify the asphalt (sub-step g)) while continuously grinding the asphalt so as to obtain it in the form of divided solids. The softening point of the asphalt is 150 ° C, measured according to the method of standard ASTM D36. The device used is the Ring and Ball Tester RB36 5G® sold by the company ISL.

Example 2

In the second example, selective deasphalting is carried out, ie extraction of the feed A with a heptane / toluene mixture as solvent under the operating conditions presented in table 4. <u><b> Table 4 </b>: <b> Operating conditions for selective deasphalting on load A </b></u> Ratio heptane / toluene solvents (v / v) 90/10 Solvent (s) / charge ratio (v / m) 6/1 Pressure (MPa) 4.17 Temperature (° C) 240

At the end of the extraction step, a fraction containing deasphalted oil and a mixture of heptane / toluene solvents is obtained. This fraction is subjected to a separation step so as to separate the mixture of heptane / toluene solvents and the deasphalted oil (DAO), the characteristics of which are presented in Table 5. <b><u> Table 5: Yields and characteristics of the deasphalted DAO oil obtained </u></b> CAD yield (% m / m) 90 Density 15/4 1.02 Sulfur (% m / m) 5.05 Conradson carbon (% m / m) 18 Ni + V (ppm) 120 AC7 (% m / m) 7.0

At the end of the extraction step, a fraction containing asphalt and a mixture of heptane / toluene solvents is also obtained. The withdrawal of this fraction is facilitated by the injection of a withdrawal flux: here a heavy gasoline coming from a catalytic cracking unit (step c). The fluxing / asphalt mass ratio is equal to 1.

The fraction containing the asphalt, the mixture of heptane / toluene solvents and the withdrawal flux is subjected to a separation step so as to separate the mixture of heptane / toluene solvents, the withdrawal flux from the asphalt (step d) . The asphalt is obtained with 10% mass of yield compared to the load.

The asphalt obtained subjected to a conditioning step at a temperature of 90 ° C. and at a pressure of 0.3 MPa making it possible to separate the traces of solvents and residual fluxes by stripping in particular (sub-step f)) and to solidify asphalt (sub-step g)) while continuously grinding the asphalt so as to obtain it in the form of divided solids. The softening point of the asphalt is 220 ° C, measured according to the method of standard ASTM D36. The device used is the Ring and Ball Tester RB36 5G® sold by the company ISL.

Claims (15)

1. Process for treating a hydrocarbon-based feedstock containing hydrocarbons with a content of C7 asphaltenes of at least 1% by mass relative to the feedstock, an initial boiling point of at least 340°C, and a final boiling point of at least 600°C, said process comprising the following steps:

   a) a step of extracting the feedstock using a solvent or a solvent mixture making it possible to obtain, on the one hand, at least one fraction comprising asphalt and solvent or solvent mixture, and, on the other hand, at least one fraction comprising de-asphalted oil and solvent or solvent mixture,

   b) a step of separating the fraction comprising de-asphalted oil and solvent or solvent mixture obtained from the extraction step a), making it possible to separate the de-asphalted oil from the solvent or solvent mixture introduced into the extraction step a),

   c) an optional step of injecting a withdrawal flux into the fraction comprising asphalt and solvent or solvent mixture obtained from the extraction step a),

   d) an optional step of separating the fraction comprising asphalt and solvent or solvent mixture obtained from the extraction step a), optionally as a mixture with the withdrawal flux introduced during the optional step c), making it possible to separate an asphalt fraction alone or as a mixture with a flux for withdrawal of the solvent or solvent mixture introduced into the extraction step a),

   e) an optional step of injecting a withdrawal flux into the asphalt fraction alone or as a mixture with a withdrawal flux obtained from step d),

   the process being characterized

   - in that step c) and/or e) of injecting the withdrawal flux is (are) present when the softening point of the asphalt is greater than 160°C,

   - and in that said process comprises a step of conditioning the asphalt fraction obtained from steps a) and/or c) and/or d) and/or e), in solid form, performed as successive or simultaneous substeps:

   - a substep f) during which the asphalt fraction is heated to a temperature of between 120 and 340°C and above the softening point of the asphalt,

   - a substep g) during which the asphalt separated from the solvent, from the solvent mixture and/or from the flux is cooled to a temperature below the softening point of the asphalt,

   in which

   substeps f) and g) are performed in at least two subunits or in a single unit equipped with at least one means that is capable of keeping the asphalt fraction in motion or stirring or grinding it continuously, at least one means of heating and cooling and at least means that are capable of removing the solvent, the solvent mixture and/or the flux of the process, and

   the asphalt fraction treated in substeps f) and g) has a softening point excluding solvent and excluding flux of greater than 120°C.
2. Process according to Claim 1, in which the polar solvent used is chosen from pure aromatic or naphtheno-aromatic solvents, polar solvents including hetero-elements, or a mixture thereof.
3. Process according to one of the preceding claims, in which the apolar solvent used is a solvent composed of saturated hydrocarbon(s) comprising a carbon number greater than or equal to 3, preferably between 3 and 9.
4. Process according to one of the preceding claims, in which the apolar solvent contains hydrocarbons with a carbon number greater than or equal to 4 and less than or equal to 7, very preferably, the apolar solvent contains hydrocarbons with a carbon number greater than or equal to 5 and less than or equal to 7.
5. Process according to one of the preceding claims, in which the flux is chosen from monoaromatic compounds, gasoline fractions obtained from catalytic reforming or from a thermal process such as catalytic cracking, gas oil fractions obtained from a conversion process in the absence of hydrogen, or aromatic extracts such as those obtained from lubrication oil production lines.
6. Process according to one of the preceding claims, in which, when the extraction step a) uses a combination of polar and apolar solvents, a mixture of polar and apolar solvents is injected into one point, while a solvent or a mixture of polar and apolar solvents is injected into a second point.
7. Process according to one of the preceding claims, in which the separation substep f) is performed at a temperature above the boiling point of the solvent, of the solvent mixture and/or optionally of the flux and at a pressure of between 0.1 and 2 MPa or under vacuum, or alternatively under the regime of an individual pressure operation followed by an individual vacuum operation.
8. Process according to Claim 6, in which, when the removal of at least part of the solvent, of the solvent mixture and/or optionally of the flux is performed by stripping during substep f), the pressure is below the vapour pressure of the solvent, of the solvent mixture and/or of the flux that it is desired to remove.
9. Process according to one of the preceding claims, in which substep f) includes a mechanical device for evacuating the asphalt into substep g) of the conditioning step.
10. Process according to one of the preceding claims, in which substep g) is performed at a temperature at least 25°C below the softening point, and at a pressure of between 0.1 and 2 MPa or under negative pressure, or alternatively under the regime of an individual pressure operation followed by an individual negative pressure operation.
11. Process according to one of the preceding claims, in which substep f) comprises equipment chosen from devolatilization equipment, blenders, extruding reactors, extruders, extruding blenders, kneaders, kneader reactors, mixers, mixing reactors and mixing kneaders.
12. Process according to one of the preceding claims, in which substep f) includes a mechanical device chosen from a pump optionally completed with a valve system for evacuating the asphalt into substep g) of the integrated conditioning step.
13. Process according to one of the preceding claims, in which substep g) comprises blenders, grinders extruding reactors, extruders, extruding blenders, kneaders, kneader reactors, mixers, mixing reactors and mixing kneaders.
14. Process according to one of the preceding claims, in which substep g) includes a mechanical device chosen from a vibrating tube optionally completed with means for evacuating the asphalt in solid form towards storage.
15. Process according to one of the preceding claims, in which the solid asphalt obtained from substep g) is in the form of asphalt pieces chosen from ground matter, extruded matter or powder, the largest dimension of which does not exceed 10 cm, preferably 5 cm.

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